It's right for God to slaughter people any time He pleases. God gives life and He takes it away. Life is in God's hands. God decides when your last heart beat will be and whether it's by natural causes, murder etc. Whether you are 1 day old, 10 years old or 100 years old.
God owns us nothing. If you are killed today, He will do no wrong to you. We might not understand it, but God governs, His will is done and you cannot change it.
Maybe someone says it's harsh, but...we are all sinners and we all deserved to die yesterday and go to hell. Many argue that they don't deserve hell, they haven't killed, they didn't harm anyone, yes they done some small sins but they are not worthy of hell. But that is our point of view not God's, because even the smallest sin is deadly, even the smallest sin is telling to Creator, I know better than you, you are wrong. It is elevation above God. Whoever sins makes them self saying 'I am better than you God, I am above you'
We cannot expect sinners to understand this, but it is truth. Therefore shows sinners the mercy of God.
When Adam and Eva sinned they should have died there and then and with them the whole humanity. But God interfered and promised a Messiah. He is the Creator, everything was created for Him, and if He wishes, He could destroy the creation any time He pleases. And creation rebelled against God, yet how many times God showed His love for the fallen and kept the Messianic line? How many evil things we done? To the point God regretted creating us, because none were righteous and none are. No one seeks God, no one repents, everyone just does evil, yet He still creates live, brings the sun up, sends rain, gives nutritious soil. Everything good that ever happens to us is God's grace. We deserve nothing. What do we deserve? Does God owe us anything?
Look at Exodus. God did numerous miracles, for Egyptians to let the Hebrews go, He split the sea for them yet the Hebrews complained. Moses went to the mountain and they build them self a golden cow, and yet God didn't slaughter them all. He sent them food from Heaven, water from a rock, but the Hebrews still wanted to go back to Egypt. Yet God forgave. He even paid for our sins and He only asks for faith and love.
Despite our evil, He gave up His glory in Heaven, came down to Earth and served us, healed us, did good to us, and what do we do? Spit on Him, laugh at Him, beat Him, crucify Him. Jesus on the cross suffered all the pain at once, yet He asked His Father to forgive us.
The Old Testament is full of our rebellion, to the point I am asking God 'why do you even bother with us, just destroy us and be done with sin' yet OT is full of God mercies and love. Despite all we done He still shows His love.
Tell that to people, because the OT is full of our rebellion yet God is full of goodness. Remember, everything good that happens is from God, we do nothing to deserve even the smallest good thing. But as is love is true, He is rightful judge also, and no sin will go unpunished, so unless you repent and now down to Jesus, one day you and your sins will have to face God. And if you rejected God your whole life, He will reject you also.